mm: use two zonelist that are filtered by GFP mask
Currently a node has two sets of zonelists, one for each zone type in the
system and a second set for GFP_THISNODE allocations. Based on the zones
allowed by a gfp mask, one of these zonelists is selected. All of these
zonelists consume memory and occupy cache lines.
This patch replaces the multiple zonelists per-node with two zonelists. The
first contains all populated zones in the system, ordered by distance, for
fallback allocations when the target/preferred node has no free pages. The
second contains all populated zones in the node suitable for GFP_THISNODE
allocations.
An iterator macro is introduced called for_each_zone_zonelist() that interates
through each zone allowed by the GFP flags in the selected zonelist.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 451eaa1..d5c33a0 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -393,10 +393,10 @@
* The NUMA zonelists are doubled becausse we need zonelists that restrict the
* allocations to a single node for GFP_THISNODE.
*
- * [0 .. MAX_NR_ZONES -1] : Zonelists with fallback
- * [MAZ_NR_ZONES ... MAZ_ZONELISTS -1] : No fallback (GFP_THISNODE)
+ * [0] : Zonelist with fallback
+ * [1] : No fallback (GFP_THISNODE)
*/
-#define MAX_ZONELISTS (2 * MAX_NR_ZONES)
+#define MAX_ZONELISTS 2
/*
@@ -464,7 +464,7 @@
unsigned long last_full_zap; /* when last zap'd (jiffies) */
};
#else
-#define MAX_ZONELISTS MAX_NR_ZONES
+#define MAX_ZONELISTS 1
struct zonelist_cache;
#endif
@@ -486,24 +486,6 @@
#endif
};
-#ifdef CONFIG_NUMA
-/*
- * Only custom zonelists like MPOL_BIND need to be filtered as part of
- * policies. As described in the comment for struct zonelist_cache, these
- * zonelists will not have a zlcache so zlcache_ptr will not be set. Use
- * that to determine if the zonelists needs to be filtered or not.
- */
-static inline int alloc_should_filter_zonelist(struct zonelist *zonelist)
-{
- return !zonelist->zlcache_ptr;
-}
-#else
-static inline int alloc_should_filter_zonelist(struct zonelist *zonelist)
-{
- return 0;
-}
-#endif /* CONFIG_NUMA */
-
#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
struct node_active_region {
unsigned long start_pfn;
@@ -731,6 +713,45 @@
zone; \
zone = next_zone(zone))
+/* Returns the first zone at or below highest_zoneidx in a zonelist */
+static inline struct zone **first_zones_zonelist(struct zonelist *zonelist,
+ enum zone_type highest_zoneidx)
+{
+ struct zone **z;
+
+ /* Find the first suitable zone to use for the allocation */
+ z = zonelist->zones;
+ while (*z && zone_idx(*z) > highest_zoneidx)
+ z++;
+
+ return z;
+}
+
+/* Returns the next zone at or below highest_zoneidx in a zonelist */
+static inline struct zone **next_zones_zonelist(struct zone **z,
+ enum zone_type highest_zoneidx)
+{
+ /* Find the next suitable zone to use for the allocation */
+ while (*z && zone_idx(*z) > highest_zoneidx)
+ z++;
+
+ return z;
+}
+
+/**
+ * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
+ * @zone - The current zone in the iterator
+ * @z - The current pointer within zonelist->zones being iterated
+ * @zlist - The zonelist being iterated
+ * @highidx - The zone index of the highest zone to return
+ *
+ * This iterator iterates though all zones at or below a given zone index.
+ */
+#define for_each_zone_zonelist(zone, z, zlist, highidx) \
+ for (z = first_zones_zonelist(zlist, highidx), zone = *z++; \
+ zone; \
+ z = next_zones_zonelist(z, highidx), zone = *z++)
+
#ifdef CONFIG_SPARSEMEM
#include <asm/sparsemem.h>
#endif